1. Field of the Invention
The embodiments described below relate to a substrate transfer apparatus, a substrate processing apparatus, a method for unloading a substrate, and a memory medium.
2. Description of Background Art
For performing treatment such as cleaning and the like on a substrate, a substrate processing apparatus successively takes wafers out of a cassette in which multiple substrates are accommodated and transfers them to a processing section and performs treatment on the substrate in the processing section (see JP2012-222254 A, for example).
In such a substrate processing apparatus, if the amounts of positional shifting of all the substrates in a cassette detected by a mapping process are within a predetermined range, the substrates are unloaded from the cassette, but if the positional shifting of any substrate is beyond the predetermined range, the apparatus determines there is an abnormality and thus cancels the unloading process of the wafers from the cassette. The entire contents of this publication are incorporated herein by reference.